The Biological Response Resource (BRR) will examined the interactions of exogenous and endogenous chemicals with our biological molecules as they are necessary for there to be a biological effect. One of the most important and practical reasons to include the biological response is that the vast majority of exposures are transient. The chemicals underlying exposures that occurred weeks, months, or years ago are long gone from the body. However, these past chemical exposures often leave molecular fingerprints of their presence. Whether this be damaged DNA, epigenetic modification, or protein adduct formation, the biological fingerprints may be able to provide information of these transient exposures of the past. Without the specific inclusion of the biological impact of exposures in the working definition of the exposome we are left with no way to assess prior exposures at a biological level. The overall goal of the Biological Response Resource BRR is to provide expertise and access to a suite of validated measures of biological responses. In order to offer maximal flexibility to potential users, our BRR is offering a wide array of assays that range from genomic and epigenomic offerings to measures of redox status, cytokine production, and pathway analysis. The goal will be pursued through the following objectives: Objective 1. To educate investigators on the benefits of biological assays available and assist in study design and sample optimization. Objective 2. To provide state-of-the-art measurements that assess the biological effects of, and susceptibility to, exposures on the human genome. Objective 3. To provide access to a variety of other indices of biological response, such as comprehensive profiling of redox state, multiplexed cytokine assessment, and microbiome characterization. Objective 4. To collaborate with the Untargeted Research Resource to identify biological responses that can be measured as part of the untargeted (metabolomics) analysis. Objective 5. To interface with the Developmental Research Resource and the Targeted Research Resource to identify biological markers which are highly associated with specific exposures. The Biological Response Resource will work with CHEAR clients, NEALE colleagues, and the entire CHEAR network to develop reliable and reproducible indices of environmentally-induced perturbations of biological systems.